Two types of diet – standard and atherogenic – were used to study the effect of wheat or wheat–rye breads supplemented with 20 % acid whey concentrate after ultrafiltration on the physiological response of growing rats. The acid whey concentrate after ultrafiltration used in rat diets caused reduced weight gain (for atherogenic diet with wheat bread); growth of caecum tissue and digesta weight; a decrease in the pH of caecum digesta (for atherogenic diet); reduced activity of bacterial glycolytic enzymes; and a significant increase in total SCFA for both types of diet with wheat–rye breads containing acid whey concentrate. For wheat bread with acid whey, in standard diet, a statistically significant increase was found in the population of bifidobacteria. The results showed that the acid whey concentrates could be used as a valuable food ingredient.
